Front-end-of-line (FEOL) processing refers to the formation of electronic devices (such as transistors) directly in the semiconductor material, e.g., silicon or nitride-based compound semiconductor materials. The semiconductor material is usually formed on a thin disc called a wafer. Back-end-of-line (BEOL) processing refers to the second part of the manufacturing process wherein the individual devices are interconnected with metal (e.g., patterned lines or traces) on the surface of the wafer. After BEOL processing, post-fabrication processing (also commonly referred to as backend processing) is performed. The backend process steps typically include wafer test, wafer backgrinding (also called backlapping or wafer thinning), die separation, die testing, packaging and final device testing.
Most often, semiconductor wafers are manufactured with a thickness that ensures mechanical stability during FEOL and BEOL processing. Depending on the material type, for example, a 4-inch diameter wafer having a thickness of between roughly 650-750 μm usually provides sufficient stability to avoid cracking and warping during high-temperature processing steps. Wafer backgrinding is the backend process step during which wafer thickness is reduced to make die separation easier and also to allow for high density packaging of integrated circuits (ICs). Die separation is where the individual die or microchips are singulated. The separation process typically involves mechanically cutting or scribing the wafer (e.g., using a laser), then breaking the wafer along the scribe lines to separate the individual die.
Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.